我是安卓的初学者。 但是我在将android studio中的数据添加到phpMyAdmin时遇到了问题。 我找到了一个准备好的代码，但是由于某种原因，当我点击按钮时，应用程序崩溃了。 我认为问题出在“networkcalls”上。<>如果我删除它，那么应用程序不会崩溃，但不会执行该功能。

activity:<?xml version="1.0" encoding="utf-8"?>

xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

tools:context="com.test.test.ScreenOne">

android:id="@+id/etUsername"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:ems="10"

android:inputType="textPersonName"

android:text="Name"

android:layout_centerHorizontal="true"

android:layout_marginTop="330dp"/>

android:id="@+id/etPassword"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:ems="10"

android:inputType="textPassword"

android:layout_centerHorizontal="true"

android:layout_marginTop="400dp"/>

android:id="@+id/bSave"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="save"

android:layout_centerHorizontal="true"

android:layout_marginTop="600dp"

android:onClick="saveb"/>

MainCode:package com.test.test;

import android.app.ProgressDialog;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.view.Window;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

import com.android.volley.AuthFailureError;

import com.android.volley.Request;

import com.android.volley.Response;

import com.android.volley.VolleyError;

import com.android.volley.toolbox.StringRequest;

import java.util.HashMap;

import java.util.Map;

public class ScreenOne extends AppCompatActivity {

private static final String URL_SAVE = "http://IP/save.php";

private EditText username;

private EditText password;

Button save;

String name;

String pass;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.screen_one);

username = (EditText) findViewById(R.id.etUsername);

password = (EditText) findViewById(R.id.etPassword);

save = (Button) findViewById(R.id.bSave);

}

public void saveb(View view) {

saveRequest();

}

private void saveRequest() {

name = username.getText().toString().trim();

pass = password.getText().toString().trim();

final ProgressDialog mDialog = new ProgressDialog(this);

mDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);

mDialog.setMessage("Loading...");

mDialog.show();

StringRequest request = new StringRequest(Request.Method.POST, URL_SAVE,

new Response.Listener() {

@Override

public void onResponse(String response) {

mDialog.dismiss();

Toast.makeText(ScreenOne.this, response, Toast.LENGTH_LONG).show();

username.setText("");

password.setText("");

}

},

new Response.ErrorListener() {

@Override

public void onErrorResponse(VolleyError error) {

mDialog.dismiss();

Toast.makeText(ScreenOne.this, "Something went wrong", Toast.LENGTH_LONG).show();

}

}) {

@Override

protected Map getParams() throws AuthFailureError {

Map key = new HashMap<>();

key.put("username", name);

key.put("password", pass);

return key;

}

};

NetworkCalls.getInstance().addToRequestQueue(request);

}

}

网络呼叫:package com.test.test;

import android.content.Context;

import com.android.volley.Request;

import com.android.volley.RequestQueue;

import com.android.volley.toolbox.Volley;

public class NetworkCalls {

private RequestQueue requestQueue;

private static Context context;

private static NetworkCalls ourInstance = new NetworkCalls();

public static NetworkCalls getInstance() {

return ourInstance;

}

private NetworkCalls() {

}

public RequestQueue getRequestQueue(){

requestQueue = Volley.newRequestQueue(context.getApplicationContext());

return requestQueue;

}

public void addToRequestQueue(Request request){

getRequestQueue().add(request);

}

}